We used creel survey data collected from 1975 to 2006 to evaluate temporal changes in the voluntary release of legally harvestable largemouth bass Micropterus salmoides at four Texas reservoirs and two Florida lakes noted for providing high‐quality largemouth bass fisheries. The voluntary release rate increased substantially over time at all six water bodies and reached asymptotic levels exceeding 0.90 in two Texas reservoirs in the early 2000s. Year explained from 68% to 96% of the variability in voluntary release rates. The level of voluntary release ranged from 0.53 to 0.99 among Texas reservoirs in the early 2000s. The increase in voluntary release over time was similar at the two Florida lakes, which had identical largemouth bass harvest regulations, but the levels differed. Catch and release of legally harvestable largemouth bass was more prevalent than harvest at five of the six water bodies included in this study but also varied across small spatial scales. Fishery managers should measure the level of voluntary release and be mindful of the potential effects of high voluntary release when considering the use of harvest restrictions to restructure largemouth bass populations.

Much of recent ecological theory rests petition with individuals of another popon the assumption that the primary factor ulation in the same environment. The responsible for the organization of natural characters may be morphological, ecologcommunities, particularly of animals, is ical, behavioral, or physiological and the interspecific competition (e.g., Mac-change may be either divergent or con- Arthur, 1972; Schoener, 1975). The valid-vergent. By divergent competitive charity of this assumption depends almost ex-acter displacement we mean that a charelusively on inference drawn from acter state of a population in ecological observational evidence of two types. Mor-sympatry (= syntopy, Rivas, 1964) exphological changes in the form of ecolog-hibits greater difference than is the case ical character displacement (Brown and when allopatric populations are contrast- Wilson, 1959;Grant, 1972) and niche ed, and that this effect can be attributed shifts correlated with geographic variation to sympatry. If the contrast of allopatric in the number or density of closely related and sympatric populations reveals that the species are generally considered the character states of the two populations are strongest available evidence for the im-more similar in areas of sympatry than in portance of interspecific competition areas of allopatry and if this effect can be (MacArthur, 1972;Cody, 1974; Schoener, attributed to competition, then the situa-1974 Schoener, attributed to competition, then the situa- , 1975

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